Open AccessInhibition of Transcription of the Histidine Operon In Vitro by the First Enzyme of the Histidine Pathway
Author(s) -
Francesco Blasi,
Carmelo B. Bruni,
A. Avitabile,
Roger G. Deeley,
Robert F. Goldberger,
Marilyn Meyers
Publication year - 1973
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.70.9.2692
Subject(s) - operon , gal operon , histidine , l arabinose operon , trp operon , transcription (linguistics) , rna , messenger rna , biology , microbiology and biotechnology , biochemistry , dna , histidine decarboxylase , in vitro , enzyme , gene , escherichia coli , linguistics , philosophy
Anin vitro system was developed for transcription of the histidine operon ofEsherichia coli carried in the genome of a defective ϕ80 transducing phage. The messenger RNA (mRNA) of the histidine operon synthesized in thein vitro system was detected by hybridization to single strands of both ϕ80 and ϕ80dhis DNA, and by competition of this hybridization with unlabeled histidine mRNA that had been synthesizedin vivo (RNA extracted from cells in which the histidine operon had been derepressed). Under the conditions used, RNA complementary to the histidine operon was about 15% of the total RNA that was synthesizedin vitro from the ϕ80dhis DNA template. The RNA complementary to the histidine operon was synthesized on the “sense” strand (the R strand) of ϕ80dhis in the form of a polycistronic message with a sedimentation coefficient (about 38 S) very close to that observed for the histidine mRNA synthesizedin vivo . Synthesis of the histidine operon RNA appears to be subject to controlin vitro . Addition of the first enzyme of the pathway for histidine biosynthesis blocked transcription of the histidine operon specifically, strongly suggesting that this enzyme acts as a regulatory protein for the histidine operon.